Rewrite ${((7^{-12})(9^{-9}))^{-5}}$ in the form ${7^n \times 9^m}$.
${ ((7^{-12})(9^{-9}))^{-5} = (7^{(-12)(-5)})(9^{(-9)(-5)})} $ ${\hphantom{ ((7^{-12})(9^{-9}))^{-5}} = 7^{60} \times 9^{45}} $